The present invention is drawn to an open cycle ocean thermal energy conversion plant which derives power from the thermal difference between surface and subsurface ocean waters.
Many devices have been proposed in an attempt to utilize the thermal qualities of ocean water to obtain useful electrical power. Specifically, these devices are arranged to operate in response to the thermal differences which exist between high-temperature surface water and low-temperature deep water. These devices are generally classified as closed or open systems.
In a "closed" system, a working medium (e.g., ammonia) is cycled from a sealed reservoir which is located in cold ocean water. The medium is pumped from the reservoir to a portion of the system located in warm ocean water which vaporizes the medium. The vaporized medium continues in its path and drives a turbine or similar power generator. From the turbine the vaporized medium is directed towards the reservoir, where the cold water surrounding the reservoir condenses the medium for further use.
An "open" system utilizes sea water and its vapor as the working medium. Warm water is pumped from the surface of the ocean to a flash evaporator maintained at low pressure that vaporizes the sea water. The vaporized sea water drives a turbine as in the closed system and then proceeds to a condenser. In the open system, cold ocean water is pumped into the condenser to condense the vaporized sea water which is then delivered back to the sea. Hybrid systems have also been proposed which utilize features of the open and closed systems.